So, what is AESA Radar

I am sure you have all heard about AESA and while all of us understand that it is an important piece of technology, many of us don't understand what makes AESA radar's good. Well, I hope the following information will help you guys better understand what AESA is and what makes it so good.

So basically, AESA stands for Active Electronically Scanned Array. In an AESA radar the transmitter and the receiver are composed of numerous small T/R modules. AESA radar has instantaneous scanning that have low probability of intercept. They have simple designs because they require no hydraulics or hinges for antenna movement. Its less infrastructure and with no motion so it is cheaper to maintain. Some more main advantages are that they have extremely fast scanning, multiple target tracking, can also function as a radio jammer and the low probability of interception.

The Russian company Phazotron unveiled the Zhuk AE AESA radar installed on the MiG-35AESA radars are emitting not only radar signals, but can also be employed for non traditional ISR, as well as electronic attack. For example, some of the elements can transmit and receive signals modulated with datalink waveform, transferring large amounts of data (such as live video or aerial imagery) over high bandwidth datalinks. Similar techniques can be used for electronic attack, to jam or deceive electronic systems operated by enemy forces.

The mechanical scanning systems used in previous systems were prone to failures, which grounded the entire aircraft. The new systems use solid-state technology and electronic scanning, to replace the mechanical systems but also introduce multiple elements to replace the single channel design of previous systems. Therefore, AESA radars can sustain certain degree of failure without grounding the aircraft or disabling the entire radar system. Furthermore, when designed with modular approach, AESA radars can be gradually upgraded, by replacing the solid-state receive/transmit modules based on Gallium-arsenide semiconductors technology with more advanced elements, thus significantly improving performance.

The Zhuk Radar on the MIG-35

AESA radars have

* High ECM resistance:
o The extremely fast scan of the radar makes it difficult for an ECM device to find the correct azimuth and elevation in which the radar's main lobe is currently directed.
o High gain associated with AESA radars gives them high ERP, which makes it difficult for an active ECM device, using noise jamming techniques, to successfully jam such a radar.
* The extremely fast scan of the emitter gives it LPI features.
* Less susceptibility to voltage failures, due to the relatively very low voltage in which each and every single radiating element operates; This is combined with graceful degradation.

In a passive electronically scanned array (PESA), the microwave feed network in the back of the antenna is driven by a single high-power Radio frequency(RF) source (transmitter), sending its waves into phase shift modules (usually digitally-controlled), which, in turn, feed the transmitting/receiving elements.Using beam steering they provide stealth, interleaving modes and reliability. However, the shift in phase of the radar signal comes at a cost. High-power phase control leads to losses in the signal and a consequent reduction in radar sensitivity. Typical total losses in early systems resulted in a factor of 10 reductions in radiated power; in modern systems these losses are still in the factor of 5 ranges.

Electronic steering and shaping of a beam provides unprecedented beam agility - beam shape and direction can be digitally controlled by a computer within a matter of tens of milliseconds. Such beam agility makes it possible for one phased array radar to act as multiple radars each with its own beam shape and scan pattern! This is referred to as interleaving radar modes. The same radar can be tracking for airborne threats using one beam shape and scan pattern while searching for ground targets using another beam shape and scan pattern.

The Russian NIIP N-011M Bars radar fitted on the Su-30MKI and the NIIP Bars-29 radar proposed to be fitted on the MiG-29M2 being offered to the IAF are examples of phased array radars

AESA

An AESA, instead, has an individual RF source for each of its many transmitting elements. This provides for a graceful degradation, so that many T/R(transmitter-receiver) modules may fail and the radar would not stop functioning. AESA employs a grid of hundreds of small (TR) modules that are linked together by high-speed processors. Each TR module has its own transmitter, receiver, processing power, and a small spikelike radiator antenna on top. The TR module can be programmed to act as a transmitter, receiver, or radar. The TR modules in the AESA system can all work together to create a powerful radar, but they can do different tasks in parallel, with some operating together as a radar warning receiver, others operating together as a jammer, and the rest operating as a radar. TR modules can be reassigned to any role, with output power or receiver sensitivity of any one of the "subsystems" defined by such temporary associations proportional to the number of modules.

AESA provides 10-30 times more net radar capability plus significant advantages in the areas of range resolution, countermeasure resistance and flexibility. In addition, it supports high reliability / low maintenance goals, which translate into lower lifecycle costs. Since the power supplies, final power amplification and input receive amplification, are distributed, MTBF is significantly higher, 10-100 times, than that of a passive ESA or mechanical array. This results in higher system readiness and significant savings in terms of life cycle cost of a weapon system, especially a fighter.

CONCLUSIONS

So, in summary A PESA radar is simpler to construct than an AESA. However, they both their drawbacks. Due to the heat generated by these devices, there has to be a very good cooling system on board to make sure that they don't fry themselves. In addition, another problem is that they have a somewhat limited range. With that said, this is really not a big concern right now because of the fact that the majority of the countries that use these radars have a well built network of Land based radar in addition to AWACS support. This will help overcome the shortages of AESA and the PESA radars.

With that said, The advantages of AESA and PESA are numerous - they can scan an area much faster (miliseconds compared to seconds), their signals are much harder to detect, and some advanced AESA models can scan, track and even work as a jammer at the same time. Advanced versions can also scan for air and ground targets at the same time in addition to tracking much more targets than normal radar. With that said, AESA is the future of radar technology as it offers features that cannot be matched by any other radar platform. Its combination of high durability and its potential for tremendous multi-tasking makes it an attractive options for countries that seek to build a modern air force.
Like I have already stated, AESA radars are remarkably good at multi tasking. In addition to emitting radar signals, then can also be employed for non traditional ISR, as well as electronic attack. For example, some of the elements can transmit and receive signals modulated with datalink waveform, transferring large amounts of data (such as live video or aerial imagery) over high bandwidth datalinks. Similar techniques can be used for electronic attack, to jam or deceive electronic systems operated by enemy forces.

The mechanical scanning systems used in previous systems were prone to failures, which grounded the entire aircraft. The new systems use solid-state technology and electronic scanning, to replace the mechanical systems but also introduce multiple elements to replace the single channel design of previous systems. Therefore, AESA radars can sustain certain degree of failure without grounding the aircraft or disabling the entire radar system. Furthermore, when designed with modular approach, AESA radars can be gradually upgraded, by replacing the solid-state receive/transmit modules based on Gallium-arsenide semiconductors technology with more advanced elements, thus significantly improving performance.

*NOTE: AFTER A LOT OF RESEARCH I HAVE PUT TOGETHER THIS INFO....AS SUCH I AM UNABLE TO CITE SOURCES BECAUSE WELL...CITING ALL THOSE SOURCES WOULD TAKE ABOUT A PAGE*

*Note, I have also posted this under the Radar thread that Lethal force made*

Nice informative articles pyro, i think DRDO have a few labs working on electronics and solid state devices e.g Anurag lab,semiconductor lab chandigarh DRDO has also developed a few floating point processers and they are trying to upgrade these labs with 0.32 micron facility for chip fabrication and working on making GaAs devices. Hope they will come out with MMR and a AESA in near future.

Advantages that AESA enjoy over PESA are : -
(1) AESA don't need oscilators and other releated electronics as the is no physical movement thus reducing response time.
It also doesn't require complex hydrolics.
(2) AESA can change frequency rapidly due to many T/R Module.
(3) AESA can even scan with several frequencies simultaniously
due to many T/R Module.
(4) Third point is also the reason why a AESA can jam other PESA radar with right software.
There are many such advantages.
The biggest difficulty in designing a AESA is that AESA uses semi-conductor technology for T/R Modules and PESA can be built using metal coil.